分光光度计打开电源开关后．应该先调零再选择工作波长。
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直流电可方便地用变压器升压或降压。
A. 对
B. 错
The mid-18th centres was predominated by a newly rising literary form ______, which gives a realistic presentation of life of the common English people.
A. [A] the traditional romance of aristocrats
B. [B] the modern English novel
C. [C] the modern English drama
D. [D] the traditional English poem
误差是用来衡量测量结果的准确度和精密度的。
A. 对
B. 错
The strikers are denied entry into the US because_______.
AIDS virus has been found among them.
B. they cannot get political asylum in the US.
C. the US government has refused to take them.
D. they don’’t accept proper medical treatment.
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